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61.
Nicole R. London John R. Garbe Sheila M. Schmutz Mitchell S. Abrahamsen Yang Da 《Mammalian genome》2003,14(4):261-267
Abstract
Statistical methods are developed to estimate gender-specific and gender-average recombination frequencies between a biallelic
or multiallelic marker and a sex-influenced gene. Iterative solutions are developed for intercross (or F-2 design). For biallelic
markers, two iterative solutions are required, one for coupling and repulsion parental linkage phases and one for mixed parental
linkage phases. For multiallelic markers, one set of iterative equations applies to all possible parental linkage phases.
The resulting formulae for estimating recombination frequency use the full data set and yield estimates that are exactly the
same as the true parameters if the observed and expected phenotypic distributions are equal. When one parent is homozygous
for the sex-influenced gene as is expected with the backcross design, simple solutions exist for estimating recombination
frequencies. However, offspring of one gender (male or female) do not have linkage information depending on whether the homozygous
parent has two male-dominant or male-recessive alleles. Consequently, an F-2 design is more efficient than a backcross design
for mapping a sex-influenced gene. Knowing each parental linkage phase is important to apply the methods developed in this
article. It is shown that an individual's linkage phase of the sex-influenced locus can be determined based on allele transmission
from the parents for all crosses except under the mating between an expressed male and an unexpressed female. 相似文献
62.
Ritha JA Njau Don de Savigny Lucy Gilson Eleuther Mwageni Franklin W Mosha 《Malaria journal》2009,8(1):1-27
Background
In the past decade there has been increasing visibility of malaria control efforts at the national and international levels. The factors that have enhanced this scenario are the availability of proven interventions such as artemisinin-based combination therapy, the wide scale use of insecticide-treated nets (ITNs) and a renewed emphasis in indoor residual house-spraying. Concurrently, there has been a window of opportunity of financial commitments from organizations such as the Global Fund for HIV/AIDS, Tuberculosis and Malaria (GFATM), the President's Malaria Initiative and the World Bank Booster programme.Methods
The case study uses the health policy analysis framework to analyse the implementation of a public-private partnership approach embarked upon by the government of Tanzania in malaria control – 'The Tanzania National Voucher Scheme'- and in this synthesis, emphasis is on the challenges faced by the scheme during the pre-implementation (2001 – 2004) and implementation phases (2004 – 2005). Qualitative research tools used include: document review, interview with key informants, stakeholder's analysis, force-field analysis, time line of events, policy characteristic analysis and focus group discussions. The study is also complemented by a cross-sectional survey, which was conducted at the Rufiji Health Demographic Surveillance Site, where a cohort of women of child-bearing age were followed up regarding access and use of ITNs.Results
The major challenges observed include: the re-introduction of taxes on mosquito nets and related products, procurement and tendering procedures in the implementation of the GFATM, and organizational arrangements and free delivery of mosquito nets through a Presidential initiative.Conclusion
The lessons gleaned from this synthesis include: (a) the consistency of the stakeholders with a common vision, was an important strength in overcoming obstacles, (b) senior politicians often steered the policy agenda when the policy in question was a 'crisis event', the stakes and the visibility were high, (c) national stakeholders in policy making have an advantage in strengthening alliances with international organizations, where the latter can become extremely influential in solving bottlenecks as the need arises, and (d) conflict can be turned into an opportunity, for example the Presidential initiative has inadvertently provided Tanzania with important lessons in the organization of 'catch-up' campaigns. 相似文献63.
64.
Tyler L. Lewis Paul L. Flint Dirk V. Derksen Joel A. Schmutz Eric J. Taylor Karen S. Bollinger 《Polar Biology》2011,34(11):1751-1762
From 1976 onward, molting brant geese (Branta bernicla) within the Teshekpuk Lake Special Area, Alaska, shifted from inland, freshwater lakes toward coastal wetlands. Two hypotheses
explained this redistribution: (1) ecological change: redistribution of molting brant reflects improvements in coastal foraging
habitats, which have undergone a succession toward salt-tolerant plants due to increased coastal erosion and saltwater intrusion
as induced by climate change or (2) interspecific competition: greater white-fronted geese (Anser albifrons) populations increased 12-fold at inland lakes, limiting food availability and forcing brant into coastal habitats. Both
hypotheses presume that brant redistributions were driven by food availability; thus, body mass dynamics may provide insight
into the relevance of these hypotheses. We compared body mass dynamics of molting brant across decades (1978, 1987–1992, 2005–2007)
and, during 2005–2007, across habitats (coastal vs. inland). Brant lost body mass during molt in all three decades. At inland
habitats, rates of mass loss progressively decreased by decade despite the increased number of greater white-fronted geese.
These results do not support an interspecific competition hypothesis, instead suggesting that ecological change enhanced foraging
habitats for brant. During 2005–2007, rates of mass loss did not vary by habitat. Thus, while habitats have improved from
earlier decades, our results cannot distinguish between ecological changes at inland versus coastal habitats. However, we
speculate that coastal forage quality has improved beyond that of inland habitats and that the body mass benefits of these
higher quality foods are offset by the disproportionate number of brant now molting coastally. 相似文献
65.
Anika I Tsuchida Michiel Beekhuizen Marieke C ‘t Hart Timothy RDJ Radstake Wouter JA Dhert Daniel BF Saris Gerjo JVM van Osch Laura B Creemers 《Arthritis research & therapy》2014,16(5)
Introduction
This study aimed to evaluate whether profiles of several soluble mediators in synovial fluid and cartilage tissue are pathology-dependent and how their production is related to in vitro tissue formation by chondrocytes from diseased and healthy tissue.Methods
Samples were obtained from donors without joint pathology (n = 39), with focal defects (n = 65) and osteoarthritis (n = 61). A multiplex bead assay (Luminex) was performed measuring up to 21 cytokines: Interleukin (IL)-1α, IL-1β, IL-1RA, IL-4, IL-6, IL-6Rα, IL-7, IL-8, IL-10, IL-13, tumor necrosis factor (TNF)α, Interferon (IFN)γ, oncostatin M (OSM), leukemia inhibitory factor (LIF), adiponectin, leptin, monocyte chemotactic factor (MCP)1, RANTES, basic fibroblast growth factor (bFGF), hepatocyte growth factor (HGF), vascular growth factor (VEGF).Results
In synovial fluid of patients with cartilage pathology, IL-6, IL-13, IFNγ and OSM levels were higher than in donors without joint pathology (P ≤0.001). IL-13, IFNγ and OSM were also different between donors with cartilage defects and OA (P <0.05). In cartilage tissue from debrided defects, VEGF was higher than in non-pathological or osteoarthritic joints (P ≤0.001). IL-1α, IL-6, TNFα and OSM concentrations (in ng/ml) were markedly higher in cartilage tissue than in synovial fluid (P <0.01). Culture of chondrocytes generally led to a massive induction of most cytokines (P <0.001). Although the release of inflammatory cytokines was also here dependent on the pathological condition (P <0.001) the actual profiles were different from tissue or synovial fluid and between non-expanded and expanded chondrocytes. Cartilage formation was lower by healthy unexpanded chondrocytes than by osteoarthritic or defect chondrocytes.Conclusions
Several pro-inflammatory, pro-angiogenic and pro-repair cytokines were elevated in joints with symptomatic cartilage defects and/or osteoarthritis, although different cytokines were elevated in synovial fluid compared to tissue or cells. Hence a clear molecular profile was evident dependent on disease status of the joint, which however changed in composition depending on the biological sample analysed. These alterations did not affect in vitro tissue formation with these chondrocytes, as this was at least as effective or even better compared to healthy chondrocytes. 相似文献66.
67.
Ian K. Blaby Crysten E. Blaby-Haas Nicolas Tourasse Erik F.Y. Hom David Lopez Munevver Aksoy Arthur Grossman James Umen Susan Dutcher Mary Porter Stephen King George B. Witman Mario Stanke Elizabeth H. Harris David Goodstein Jane Grimwood Jeremy Schmutz Olivier Vallon Simon Prochnik 《Trends in plant science》2014,19(10):672-680
68.
The signal produced by fluorescence in situ hybridization (FISH) often is inconsistent among cells and sensitivity is low. Small DNA targets on the chromatin are difficult to detect. We report here an improved nick translation procedure for Texas red and Alexa Fluor 488 direct labeling of FISH probes. Brighter probes can be obtained by adding excess DNA polymerase I. Using such probes, a 30 kb yeast transgene, and the rp1, rp3 and zein multigene clusters were clearly detected. 相似文献
69.
Fiona C Buchanan Carolyn J Fitzsimmons Andrew G Van Kessel Tracey D Thue Dianne C Winkelman-Sim Sheila M Schmutz 《遗传、选种与进化》2002,34(1):105-116
Previously, we have shown that alleles of the BM1500 microsatellite, located 3.6 kb downstream of the leptin gene in cattle, were associated with carcass fat measures in a population of 154 unrelated beef bulls. Subsequently, a cytosine (C) to thymine (T) transition that encoded an amino acid change of an arginine to a cysteine was identified in exon 2 of the leptin gene. A PCR-RFLP was designed and allele frequencies in four beef breeds were correlated with levels of carcass fat. The T allele was associated with fatter carcasses and the C allele with leaner carcasses. The frequencies of the SNP alleles among breeds indicated that British breeds have a higher frequency of the T allele whereas the continental breeds have a higher occurrence of the C allele. A ribonuclease protection assay was developed to quantify leptin mRNA in a separate group of animals selected by genotype. Animals homozygous for thymine expressed higher levels of leptin mRNA. This may suggest that the T allele, which adds an extra cysteine to the protein, imparts a partial loss of biological function and hence could be the causative mutation. 相似文献
70.
G. Chen B. Schmutz D. Epari K. Rathnayaka S. Ibrahim M.A. Schuetz M.J. Pearcy 《Journal of biomechanics》2010,43(5):1011-1015
Generation of subject-specific finite element (FE) models from computed tomography (CT) datasets is of significance for application of the FE analysis to bone structures. A great challenge that remains is the automatic assignment of bone material properties from CT Hounsfield Units into finite element models. This paper proposes a new assignment approach, in which material properties are directly assigned to each integration point. Instead of modifying the dataset of FE models, the proposed approach divides the assignment procedure into two steps: generating the data file of the image intensity of a bone in a MATLAB program and reading the file into ABAQUS via user subroutines. Its accuracy has been validated by assigning the density of a bone phantom into a FE model. The proposed approach has been applied to the FE model of a sheep tibia and its applicability tested on a variety of element types. The proposed assignment approach is simple and illustrative. It can be easily modified to fit users’ situations. 相似文献